How might an increase in the size of the sparrow population affect the orange-bellied parrot population?

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.

the answer to your question is tooth decay.

the fossil record provides evidence of a common ancestor to many species.

i think the answer is a.keratin is the pigment responsible for skin color.